There is a large disparity in the literature regarding the effect of age on perception of pain. Various studies have shown both an increase and a decrease in pain sensitivity with age. Studies also exist that have reported no signficant change in pain sensitivity with age. A number of cerebral structures that receive and process nociceptive input originating from the body including the post-central gyrus (primary somatosensory cortex - $1), the posterior parietal operculum ( which includes the secondary somatosensory cortex - $1), the insula, and portions of the anterior cingulate cortex have been identified in mammals by various neuranatomical and neurophysiological studies. The overall objective of this study is to use quantitative psychophysics and functional MRI (fMRI) techniques to determine whether age influences the cerbral activation patterns associated with noxious mechanical stimulation. One component of this project is to determine the effect of age on suprathreshold pain perception using standard psychophysical testing methods. A second aim of this project is to determine the effect of age on cortical processing of nociceptive information. Specifically we would like to understand the processing of stimulus intensity encoding with age, the extent of involvement of the cerebral cortex, and the latency in the hemodynamic response between the young adults and the elderly. A third aim is to determine whether age differences influence variability in the fMRI response, and whether such variability (both intra- & inter-subject) impacts fMRI analysis & interpretation. We propose to test this hypothesis on two distinct age groups in the age range of 18-30 years and 55-70 years. FMRI data from the individuals would be obtained multiple times from which functional reliability maps will be generated for each subject. Individual data will then be grouped into each of the two age ranges and quantitative information on the above parameters will be generated and compared with the psychophysical pain ratings. To date their have been no studies looking into the effect of age with nociception processing using functional brain imaging. It is anticipated that the results from this project will enhance our knowledge of how the pain related processes change with age.